Federated Naming Service (FNS) provides a method
for federating multiple naming services under a single, simple interface
for the basic naming operations. One of the naming services supported by FNS is the X.500 Directory Service (see ITU-T X.500 or ISO/IEC
9594). X.500 is a global directory service. Its components cooperate to
manage information about a hierarchy of objects on a worldwide scope. Such
objects include countries, organizations, people, services, and machines. FNS uses X.500 to name entities globally.

FNS provides the XFN interface for retrieval and modification of information stored
in X.500. In addition, enterprise namespaces such as those served by NIS+ and NIS can
be federated with X.500 by adding reference information to X.500 describing
how to reach the desired next naming service. To federate a NIS+ or NIS namespace under X.500,
perform the following steps:

Obtain the root reference for the NIS+ hierarchy or NIS domain.

Enhance the X.500 schema to support the addition
of XFN references.

Create an X.500 entry to store the XFN reference.

Add the XFN
reference.

The root reference is referred to as the nextnamingsystemreference because it refers to the next
naming system beneath X.500. This reference contains information about how
to communicate with the NIS+ or NIS servers and has the following format:

<domainname> <server
name> [ <server address> ]

where <domainname> is the fully qualified
domain name. Notice that NIS+ and NIS have slightly different syntaxes for domain
names. For NIS+, the fully qualified domain
name is case-insensitive and terminated by a dot character ('.'). For NIS, the fully qualified
domain name is case-sensitive and not terminated
by a dot character. For both NIS+ and NIS, <serveraddress> is optional. If it is not supplied, a host name lookup
will be performed to get the machine's address.

For example, if the machine wiz-nisplus-server
with address 133.33.33.33 serves the NIS+ domain wiz.com., the reference would look
like this:

wiz.com.wiz-nisplus-server133.33.33.33

For another example, if the machine woz-nis-server
serves the NIS domain Woz.COM, the reference would look like this:

Woz.COMwoz-nis-server

Before the next naming system reference can be added to X.500, the
X.500 schema must be altered to include the following object class and associated
attributes (defined in ASN.1 notation).

The procedures for altering the X.500 schema will vary from implementation
to implementation. Consult Solstice X.500 or the
schema administration guide for your X.500 product.

Once X.500 supports XFN references,
the next naming system reference can be added by first creating an X.500
object and then adding the new reference to it. For example, the following
commands create entries for the Wiz and Woz organizations in the U.S.A. and add the reference information
shown in the examples above to them.

Notice the mandatory trailing slash ('/') in the
name argument to fnbind(1).

This modification effectively adds the next naming system reference
to X.500. The reference may be retrieved using fnlookup(1) to see if the information
has been added properly. For example, the following command looks up the
next naming system reference of the Wiz organization:

example% fnlookup -v .../c=us/o=wiz/

Note the mandatory trailing slash.

After this administrative step has been taken, clients outside of
the NIS+ hierarchy or NIS domain can access and perform operations on the contexts in
the NIS+ hierarchy or NIS domain. Foreign NIS+ clients
access the hierarchy as unauthenticated NIS+
clients. Continuing the example above, and assuming that NIS+ is federated underneath the Wiz organization,
the root of the NIS+ enterprise may be
listed using the command: